Gen Set Not Starting

[Dick Simonis]

Gads, will it never end.  Not whe Gen Set is not starting and throwing a code 46.  All was well a bit ago.  I did have the house batteries replaced but I thought the gen set start was on the chassis batteries.

Even remotely nothing at all, no preheat just dead.

Any thoughts???

[Keith Oliver]

Full Moon?

[Gerald Farris]

Dick,
Code 46 is related to low input voltage on the 12V circuit. If you have checked the 12V circuit adequately, the best thing to do is to call Onan and see if they can point you in the right direction. It is possibility a bad circuit board, but you need to troubleshoot the system thoroughly before jumping the gun and replacing something that may not be bad.

Gerald  

[David T. Richelderfer]

My generator manual does not show an error code 46.  It does show an error code 36... which says, among other things, to push and hold the generator start button to the off position for a minute.  This actuates the fuel pump and primes the system.  Then push the start button to the start position... and it damn well better start.   lol

[Gerald Farris]

David,
Your coach has a 12.5 KW constant speed generator that has a totally different control system than the 7.5 KW variable speed unit in dicks coach.

Gerald

[Dick Simonis]

Dick,
Code 46 is related to low input voltage on the 12V circuit. If you have checked the 12V circuit adequately, the best thing to do is to call Onan and see if they can point you in the right direction. It is possibility a bad circuit board, but you need to troubleshoot the system thoroughly before jumping the gun and replacing something that may not be bad.

Gerald  

Gerald,  

Thanks for the info, that's sort of what we figured but it's so odd that it was working perfectly right after out power issue and we used it for several hours in the RV park while troubleshooting all the other problems.  While it was in the shop the tech tried to start it after the new transfer switch, inverter, and house batteries were replaced and no joy, wouldn't start and threw the code 46.  As far as I know, the gen set uses the chassis batteries so I can't see how any of that would cause the problem.

The tech diagnosed the chassis batteries as being bad but in reality they were only deadish due to not having any charger working but they are only a year old and once we got a good charge in them they seem fine.  Starts the engine without using the parallel switch and the connection are clean and tight.  Than he told me the gen set inverter was shot and that I need to go to an Onan shop.  However, if that is the case wouldn't the gen set start, detect a bad board, than shut down and throw a code?

Yesterday, I pulled the plate and checked the two fuses which I believe are for the preheat and starter solenoid and they looked OK.  The codes flash a 3 rapid which seems to be a "service required" code than when I hit the stop button it flashes 4X than pause and flashes 6X so I think I'm reading the code OK.  It does not prime, nor preheat....just totally unresponsive.

At least I now have the coach at home which will make it a little easier and I should be able to find an Onan shop in Tucson.

Any more thoughts would be appreciated.

Dick

[Joel Ashley]

No matter how young a chassis battery is, it is not a deep cycle.  Even one fully or near-completely discharged will be damaged such that it will never be the same again.  And there can be bad apples among even new batteries;  if just one of the pair is faulty, it can drag down the other, though the effect is not as bad as with series-wired house batteries.  Letting chassis bats set for an extended time with a small parasitic load and no charge source will compound the issue, and though they may seem fine upon recharge, they'll never be the same again.  

Nonetheless, fully charged they should crank the genset with little problem.  First thing is checking hot and ground connections throughout the generator start circuit, including the switches and relay or solenoid.  Then use a meter to track back to the first sign of a live hot connector or wire with full voltage.  Even low bats would show some voltage at the genset post, but the fact that yours is devoid of any at all implies a loose or high impedance connection somewhere.  A wiring diagram would help such sleuthing.

It is likely more than coincidence that the unit failed upon the inverter and transfer switch replacement;  I'm not sure of your tech's competence.

What the heck is a "genset inverter" exactly?  

Joel

[Edward Buker]

A genset inverter is an electronic method of generating 60 cycles at a regulated 120v much like your inverter circuit. Because the engine is no longer responsible for maintaining 60 cycles it can run more efficiently at lower RPM and then increase the engine speed based on current demand. They typically use an alternator for power generation, whose output is then rectified into pulsating DC, followed by an inverter circuit to make sine wave AC at 120v. Here is some Honda generator info. They were some of the first to engineer this method into small gensets.

http://powerequipment.honda.com/generators/inverter-generator-advantages

This approach reduces noise, weight, and fuel consumption when you no longer need to maintain 1800 or 3600rpm all the time. This also means a lighter smaller engine can be revved higher than 3600rpm momentarily to handle starting current issues and develop the HP power needed to overcome the load. Reducing the weight of the whole unit for a given KW output was probably the biggest driver of the technology given you could then also be more compact.

Later Ed